/* * x86 SMP booting functions * * (c) 1995 Alan Cox, Building #3 * (c) 1998, 1999, 2000, 2009 Ingo Molnar * Copyright 2001 Andi Kleen, SuSE Labs. * * Much of the core SMP work is based on previous work by Thomas Radke, to * whom a great many thanks are extended. * * Thanks to Intel for making available several different Pentium, * Pentium Pro and Pentium-II/Xeon MP machines. * Original development of Linux SMP code supported by Caldera. * * This code is released under the GNU General Public License version 2 or * later. * * Fixes * Felix Koop : NR_CPUS used properly * Jose Renau : Handle single CPU case. * Alan Cox : By repeated request 8) - Total BogoMIPS report. * Greg Wright : Fix for kernel stacks panic. * Erich Boleyn : MP v1.4 and additional changes. * Matthias Sattler : Changes for 2.1 kernel map. * Michel Lespinasse : Changes for 2.1 kernel map. * Michael Chastain : Change trampoline.S to gnu as. * Alan Cox : Dumb bug: 'B' step PPro's are fine * Ingo Molnar : Added APIC timers, based on code * from Jose Renau * Ingo Molnar : various cleanups and rewrites * Tigran Aivazian : fixed "0.00 in /proc/uptime on SMP" bug. * Maciej W. Rozycki : Bits for genuine 82489DX APICs * Andi Kleen : Changed for SMP boot into long mode. * Martin J. Bligh : Added support for multi-quad systems * Dave Jones : Report invalid combinations of Athlon CPUs. * Rusty Russell : Hacked into shape for new "hotplug" boot process. * Andi Kleen : Converted to new state machine. * Ashok Raj : CPU hotplug support * Glauber Costa : i386 and x86_64 integration */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Number of siblings per CPU package */ int smp_num_siblings = 1; EXPORT_SYMBOL(smp_num_siblings); /* Last level cache ID of each logical CPU */ DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID; /* representing HT siblings of each logical CPU */ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map); EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); /* representing HT and core siblings of each logical CPU */ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map); EXPORT_PER_CPU_SYMBOL(cpu_core_map); DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map); /* Per CPU bogomips and other parameters */ DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info); EXPORT_PER_CPU_SYMBOL(cpu_info); /* Logical package management. We might want to allocate that dynamically */ static int *physical_to_logical_pkg __read_mostly; static unsigned long *physical_package_map __read_mostly;; static unsigned int max_physical_pkg_id __read_mostly; unsigned int __max_logical_packages __read_mostly; EXPORT_SYMBOL(__max_logical_packages); static unsigned int logical_packages __read_mostly; static bool logical_packages_frozen __read_mostly; /* Maximum number of SMT threads on any online core */ int __max_smt_threads __read_mostly; static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip) { unsigned long flags; spin_lock_irqsave(&rtc_lock, flags); CMOS_WRITE(0xa, 0xf); spin_unlock_irqrestore(&rtc_lock, flags); local_flush_tlb(); pr_debug("1.\n"); *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) = start_eip >> 4; pr_debug("2.\n"); *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = start_eip & 0xf; pr_debug("3.\n"); } static inline void smpboot_restore_warm_reset_vector(void) { unsigned long flags; /* * Install writable page 0 entry to set BIOS data area. */ local_flush_tlb(); /* * Paranoid: Set warm reset code and vector here back * to default values. */ spin_lock_irqsave(&rtc_lock, flags); CMOS_WRITE(0, 0xf); spin_unlock_irqrestore(&rtc_lock, flags); *((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0; } /* * Report back to the Boot Processor during boot time or to the caller processor * during CPU online. */ static void smp_callin(void) { int cpuid, phys_id; /* * If waken up by an INIT in an 82489DX configuration * cpu_callout_mask guarantees we don't get here before * an INIT_deassert IPI reaches our local APIC, so it is * now safe to touch our local APIC. */ cpuid = smp_processor_id(); /* * (This works even if the APIC is not enabled.) */ phys_id = read_apic_id(); /* * the boot CPU has finished the init stage and is spinning * on callin_map until we finish. We are free to set up this * CPU, first the APIC. (this is probably redundant on most * boards) */ apic_ap_setup(); /* * Save our processor parameters. Note: this information * is needed for clock calibration. */ smp_store_cpu_info(cpuid); /* * Get our bogomips. * Update loops_per_jiffy in cpu_data. Previous call to * smp_store_cpu_info() stored a value that is close but not as * accurate as the value just calculated. */ calibrate_delay(); cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy; pr_debug("Stack at about %p\n", &cpuid); /* * This must be done before setting cpu_online_mask * or calling notify_cpu_starting. */ set_cpu_sibling_map(raw_smp_processor_id()); wmb(); notify_cpu_starting(cpuid); /* * Allow the master to continue. */ cpumask_set_cpu(cpuid, cpu_callin_mask); } static int cpu0_logical_apicid; static int enable_start_cpu0; /* * Activate a secondary processor. */ static void notrace start_secondary(void *unused) { /* * Don't put *anything* before cpu_init(), SMP booting is too * fragile that we want to limit the things done here to the * most necessary things. */ cpu_init(); x86_cpuinit.early_percpu_clock_init(); preempt_disable(); smp_callin(); enable_start_cpu0 = 0; #ifdef CONFIG_X86_32 /* switch away from the initial page table */ load_cr3(swapper_pg_dir); __flush_tlb_all(); #endif /* otherwise gcc will move up smp_processor_id before the cpu_init */ barrier(); /* * Check TSC synchronization with the BP: */ check_tsc_sync_target(); /* * Lock vector_lock and initialize the vectors on this cpu * before setting the cpu online. We must set it online with * vector_lock held to prevent a concurrent setup/teardown * from seeing a half valid vector space. */ lock_vector_lock(); setup_vector_irq(smp_processor_id()); set_cpu_online(smp_processor_id(), true); unlock_vector_lock(); cpu_set_state_online(smp_processor_id()); x86_platform.nmi_init(); /* enable local interrupts */ local_irq_enable(); /* to prevent fake stack check failure in clock setup */ boot_init_stack_canary(); x86_cpuinit.setup_percpu_clockev(); wmb(); cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); } int topology_update_package_map(unsigned int apicid, unsigned int cpu) { unsigned int new, pkg = apicid >> boot_cpu_data.x86_coreid_bits; /* Called from early boot ? */ if (!physical_package_map) return 0; if (pkg >= max_physical_pkg_id) return -EINVAL; /* Set the logical package id */ if (test_and_set_bit(pkg, physical_package_map)) goto found; if (logical_packages_frozen) { physical_to_logical_pkg[pkg] = -1; pr_warn("APIC(%x) Package %u exceeds logical package max\n", apicid, pkg); return -ENOSPC; } new = logical_packages++; pr_info("APIC(%x) Converting physical %u to logical package %u\n", apicid, pkg, new); physical_to_logical_pkg[pkg] = new; found: cpu_data(cpu).logical_proc_id = physical_to_logical_pkg[pkg]; return 0; } /** * topology_phys_to_logical_pkg - Map a physical package id to a logical * * Returns logical package id or -1 if not found */ int topology_phys_to_logical_pkg(unsigned int phys_pkg) { if (phys_pkg >= max_physical_pkg_id) return -1; return physical_to_logical_pkg[phys_pkg]; } EXPORT_SYMBOL(topology_phys_to_logical_pkg); static void __init smp_init_package_map(void) { unsigned int ncpus, cpu; size_t size; /* * Today neither Intel nor AMD support heterogenous systems. That * might change in the future.... * * While ideally we'd want '* smp_num_siblings' in the below @ncpus * computation, this won't actually work since some Intel BIOSes * report inconsistent HT data when they disable HT. * * In particular, they reduce the APIC-IDs to only include the cores, * but leave the CPUID topology to say there are (2) siblings. * This means we don't know how many threads there will be until * after the APIC enumeration. * * By not including this we'll sometimes over-estimate the number of * logical packages by the amount of !present siblings, but this is * still better than MAX_LOCAL_APIC. * * We use total_cpus not nr_cpu_ids because nr_cpu_ids can be limited * on the command line leading to a similar issue as the HT disable * problem because the hyperthreads are usually enumerated after the * primary cores. */ ncpus = boot_cpu_data.x86_max_cores; if (!ncpus) { pr_warn("x86_max_cores == zero !?!?"); ncpus = 1; } __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus); logical_packages = 0; /* * Possibly larger than what we need as the number of apic ids per * package can be smaller than the actual used apic ids. */ max_physical_pkg_id = DIV_ROUND_UP(MAX_LOCAL_APIC, ncpus); size = max_physical_pkg_id * sizeof(unsigned int); physical_to_logical_pkg = kmalloc(size, GFP_KERNEL); memset(physical_to_logical_pkg, 0xff, size); size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long); physical_package_map = kzalloc(size, GFP_KERNEL); for_each_present_cpu(cpu) { unsigned int apicid = apic->cpu_present_to_apicid(cpu); if (apicid == BAD_APICID || !apic->apic_id_valid(apicid)) continue; if (!topology_update_package_map(apicid, cpu)) continue; pr_warn("CPU %u APICId %x disabled\n", cpu, apicid); per_cpu(x86_bios_cpu_apicid, cpu) = BAD_APICID; set_cpu_possible(cpu, false); set_cpu_present(cpu, false); } if (logical_packages > __max_logical_packages) { pr_warn("Detected more packages (%u), then computed by BIOS data (%u).\n", logical_packages, __max_logical_packages); logical_packages_frozen = true; __max_logical_packages = logical_packages; } pr_info("Max logical packages: %u\n", __max_logical_packages); } void __init smp_store_boot_cpu_info(void) { int id = 0; /* CPU 0 */ struct cpuinfo_x86 *c = &cpu_data(id); *c = boot_cpu_data; c->cpu_index = id; smp_init_package_map(); } /* * The bootstrap kernel entry code has set these up. Save them for * a given CPU */ void smp_store_cpu_info(int id) { struct cpuinfo_x86 *c = &cpu_data(id); *c = boot_cpu_data; c->cpu_index = id; /* * During boot time, CPU0 has this setup already. Save the info when * bringing up AP or offlined CPU0. */ identify_secondary_cpu(c); } static bool topology_same_node(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; return (cpu_to_node(cpu1) == cpu_to_node(cpu2)); } static bool topology_sane(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o, const char *name) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; return !WARN_ONCE(!topology_same_node(c, o), "sched: CPU #%d's %s-sibling CPU #%d is not on the same node! " "[node: %d != %d]. Ignoring dependency.\n", cpu1, name, cpu2, cpu_to_node(cpu1), cpu_to_node(cpu2)); } #define link_mask(mfunc, c1, c2) \ do { \ cpumask_set_cpu((c1), mfunc(c2)); \ cpumask_set_cpu((c2), mfunc(c1)); \ } while (0) static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { if (boot_cpu_has(X86_FEATURE_TOPOEXT)) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; if (c->phys_proc_id == o->phys_proc_id && per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2) && c->cpu_core_id == o->cpu_core_id) return topology_sane(c, o, "smt"); } else if (c->phys_proc_id == o->phys_proc_id && c->cpu_core_id == o->cpu_core_id) { return topology_sane(c, o, "smt"); } return false; } static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; if (per_cpu(cpu_llc_id, cpu1) != BAD_APICID && per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) return topology_sane(c, o, "llc"); return false; } /* * Unlike the other levels, we do not enforce keeping a * multicore group inside a NUMA node. If this happens, we will * discard the MC level of the topology later. */ static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { if (c->phys_proc_id == o->phys_proc_id) return true; return false; } static struct sched_domain_topology_level numa_inside_package_topology[] = { #ifdef CONFIG_SCHED_SMT { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, #endif #ifdef CONFIG_SCHED_MC { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, #endif { NULL, }, }; /* * set_sched_topology() sets the topology internal to a CPU. The * NUMA topologies are layered on top of it to build the full * system topology. * * If NUMA nodes are observed to occur within a CPU package, this * function should be called. It forces the sched domain code to * only use the SMT level for the CPU portion of the topology. * This essentially falls back to relying on NUMA information * from the SRAT table to describe the entire system topology * (except for hyperthreads). */ static void primarily_use_numa_for_topology(void) { set_sched_topology(numa_inside_package_topology); } void set_cpu_sibling_map(int cpu) { bool has_smt = smp_num_siblings > 1; bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1; struct cpuinfo_x86 *c = &cpu_data(cpu); struct cpuinfo_x86 *o; int i, threads; cpumask_set_cpu(cpu, cpu_sibling_setup_mask); if (!has_mp) { cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu)); cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu)); cpumask_set_cpu(cpu, topology_core_cpumask(cpu)); c->booted_cores = 1; return; } for_each_cpu(i, cpu_sibling_setup_mask) { o = &cpu_data(i); if ((i == cpu) || (has_smt && match_smt(c, o))) link_mask(topology_sibling_cpumask, cpu, i); if ((i == cpu) || (has_mp && match_llc(c, o))) link_mask(cpu_llc_shared_mask, cpu, i); } /* * This needs a separate iteration over the cpus because we rely on all * topology_sibling_cpumask links to be set-up. */ for_each_cpu(i, cpu_sibling_setup_mask) { o = &cpu_data(i); if ((i == cpu) || (has_mp && match_die(c, o))) { link_mask(topology_core_cpumask, cpu, i); /* * Does this new cpu bringup a new core? */ if (cpumask_weight( topology_sibling_cpumask(cpu)) == 1) { /* * for each core in package, increment * the booted_cores for this new cpu */ if (cpumask_first( topology_sibling_cpumask(i)) == i) c->booted_cores++; /* * increment the core count for all * the other cpus in this package */ if (i != cpu) cpu_data(i).booted_cores++; } else if (i != cpu && !c->booted_cores) c->booted_cores = cpu_data(i).booted_cores; } if (match_die(c, o) && !topology_same_node(c, o)) primarily_use_numa_for_topology(); } threads = cpumask_weight(topology_sibling_cpumask(cpu)); if (threads > __max_smt_threads) __max_smt_threads = threads; } /* maps the cpu to the sched domain representing multi-core */ const struct cpumask *cpu_coregroup_mask(int cpu) { return cpu_llc_shared_mask(cpu); } static void impress_friends(void) { int cpu; unsigned long bogosum = 0; /* * Allow the user to impress friends. */ pr_debug("Before bogomips\n"); for_each_possible_cpu(cpu) if (cpumask_test_cpu(cpu, cpu_callout_mask)) bogosum += cpu_data(cpu).loops_per_jiffy; pr_info("Total of %d processors activated (%lu.%02lu BogoMIPS)\n", num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100); pr_debug("Before bogocount - setting activated=1\n"); } void __inquire_remote_apic(int apicid) { unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 }; const char * const names[] = { "ID", "VERSION", "SPIV" }; int timeout; u32 status; pr_info("Inquiring remote APIC 0x%x...\n", apicid); for (i = 0; i < ARRAY_SIZE(regs); i++) { pr_info("... APIC 0x%x %s: ", apicid, names[i]); /* * Wait for idle. */ status = safe_apic_wait_icr_idle(); if (status) pr_cont("a previous APIC delivery may have failed\n"); apic_icr_write(APIC_DM_REMRD | regs[i], apicid); timeout = 0; do { udelay(100); status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK; } while (status == APIC_ICR_RR_INPROG && timeout++ < 1000); switch (status) { case APIC_ICR_RR_VALID: status = apic_read(APIC_RRR); pr_cont("%08x\n", status); break; default: pr_cont("failed\n"); } } } /* * The Multiprocessor Specification 1.4 (1997) example code suggests * that there should be a 10ms delay between the BSP asserting INIT * and de-asserting INIT, when starting a remote processor. * But that slows boot and resume on modern processors, which include * many cores and don't require that delay. * * Cmdline "init_cpu_udelay=" is available to over-ride this delay. * Modern processor families are quirked to remove the delay entirely. */ #define UDELAY_10MS_DEFAULT 10000 static unsigned int init_udelay = UINT_MAX; static int __init cpu_init_udelay(char *str) { get_option(&str, &init_udelay); return 0; } early_param("cpu_init_udelay", cpu_init_udelay); static void __init smp_quirk_init_udelay(void) { /* if cmdline changed it from default, leave it alone */ if (init_udelay != UINT_MAX) return; /* if modern processor, use no delay */ if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) || ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) { init_udelay = 0; return; } /* else, use legacy delay */ init_udelay = UDELAY_10MS_DEFAULT; } /* * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this * won't ... remember to clear down the APIC, etc later. */ int wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip) { unsigned long send_status, accept_status = 0; int maxlvt; /* Target chip */ /* Boot on the stack */ /* Kick the second */ apic_icr_write(APIC_DM_NMI | apic->dest_logical, apicid); pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); /* * Give the other CPU some time to accept the IPI. */ udelay(200); if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) { maxlvt = lapic_get_maxlvt(); if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); accept_status = (apic_read(APIC_ESR) & 0xEF); } pr_debug("NMI sent\n"); if (send_status) pr_err("APIC never delivered???\n"); if (accept_status) pr_err("APIC delivery error (%lx)\n", accept_status); return (send_status | accept_status); } static int wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip) { unsigned long send_status = 0, accept_status = 0; int maxlvt, num_starts, j; maxlvt = lapic_get_maxlvt(); /* * Be paranoid about clearing APIC errors. */ if (APIC_INTEGRATED(apic_version[phys_apicid])) { if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); apic_read(APIC_ESR); } pr_debug("Asserting INIT\n"); /* * Turn INIT on target chip */ /* * Send IPI */ apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT, phys_apicid); pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); udelay(init_udelay); pr_debug("Deasserting INIT\n"); /* Target chip */ /* Send IPI */ apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid); pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); mb(); /* * Should we send STARTUP IPIs ? * * Determine this based on the APIC version. * If we don't have an integrated APIC, don't send the STARTUP IPIs. */ if (APIC_INTEGRATED(apic_version[phys_apicid])) num_starts = 2; else num_starts = 0; /* * Run STARTUP IPI loop. */ pr_debug("#startup loops: %d\n", num_starts); for (j = 1; j <= num_starts; j++) { pr_debug("Sending STARTUP #%d\n", j); if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); apic_read(APIC_ESR); pr_debug("After apic_write\n"); /* * STARTUP IPI */ /* Target chip */ /* Boot on the stack */ /* Kick the second */ apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12), phys_apicid); /* * Give the other CPU some time to accept the IPI. */ if (init_udelay == 0) udelay(10); else udelay(300); pr_debug("Startup point 1\n"); pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); /* * Give the other CPU some time to accept the IPI. */ if (init_udelay == 0) udelay(10); else udelay(200); if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); accept_status = (apic_read(APIC_ESR) & 0xEF); if (send_status || accept_status) break; } pr_debug("After Startup\n"); if (send_status) pr_err("APIC never delivered???\n"); if (accept_status) pr_err("APIC delivery error (%lx)\n", accept_status); return (send_status | accept_status); } void smp_announce(void) { int num_nodes = num_online_nodes(); printk(KERN_INFO "x86: Booted up %d node%s, %d CPUs\n", num_nodes, (num_nodes > 1 ? "s" : ""), num_online_cpus()); } /* reduce the number of lines printed when booting a large cpu count system */ static void announce_cpu(int cpu, int apicid) { static int current_node = -1; int node = early_cpu_to_node(cpu); static int width, node_width; if (!width) width = num_digits(num_possible_cpus()) + 1; /* + '#' sign */ if (!node_width) node_width = num_digits(num_possible_nodes()) + 1; /* + '#' */ if (cpu == 1) printk(KERN_INFO "x86: Booting SMP configuration:\n"); if (system_state == SYSTEM_BOOTING) { if (node != current_node) { if (current_node > (-1)) pr_cont("\n"); current_node = node; printk(KERN_INFO ".... node %*s#%d, CPUs: ", node_width - num_digits(node), " ", node); } /* Add padding for the BSP */ if (cpu == 1) pr_cont("%*s", width + 1, " "); pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu); } else pr_info("Booting Node %d Processor %d APIC 0x%x\n", node, cpu, apicid); } static int wakeup_cpu0_nmi(unsigned int cmd, struct pt_regs *regs) { int cpu; cpu = smp_processor_id(); if (cpu == 0 && !cpu_online(cpu) && enable_start_cpu0) return NMI_HANDLED; return NMI_DONE; } /* * Wake up AP by INIT, INIT, STARTUP sequence. * * Instead of waiting for STARTUP after INITs, BSP will execute the BIOS * boot-strap code which is not a desired behavior for waking up BSP. To * void the boot-strap code, wake up CPU0 by NMI instead. * * This works to wake up soft offlined CPU0 only. If CPU0 is hard offlined * (i.e. physically hot removed and then hot added), NMI won't wake it up. * We'll change this code in the future to wake up hard offlined CPU0 if * real platform and request are available. */ static int wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid, int *cpu0_nmi_registered) { int id; int boot_error; preempt_disable(); /* * Wake up AP by INIT, INIT, STARTUP sequence. */ if (cpu) { boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip); goto out; } /* * Wake up BSP by nmi. * * Register a NMI handler to help wake up CPU0. */ boot_error = register_nmi_handler(NMI_LOCAL, wakeup_cpu0_nmi, 0, "wake_cpu0"); if (!boot_error) { enable_start_cpu0 = 1; *cpu0_nmi_registered = 1; if (apic->dest_logical == APIC_DEST_LOGICAL) id = cpu0_logical_apicid; else id = apicid; boot_error = wakeup_secondary_cpu_via_nmi(id, start_ip); } out: preempt_enable(); return boot_error; } void common_cpu_up(unsigned int cpu, struct task_struct *idle) { /* Just in case we booted with a single CPU. */ alternatives_enable_smp(); per_cpu(current_task, cpu) = idle; #ifdef CONFIG_X86_32 /* Stack for startup_32 can be just as for start_secondary onwards */ irq_ctx_init(cpu); per_cpu(cpu_current_top_of_stack, cpu) = (unsigned long)task_stack_page(idle) + THREAD_SIZE; #else clear_tsk_thread_flag(idle, TIF_FORK); initial_gs = per_cpu_offset(cpu); #endif } /* * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad * (ie clustered apic addressing mode), this is a LOGICAL apic ID. * Returns zero if CPU booted OK, else error code from * ->wakeup_secondary_cpu. */ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle) { volatile u32 *trampoline_status = (volatile u32 *) __va(real_mode_header->trampoline_status); /* start_ip had better be page-aligned! */ unsigned long start_ip = real_mode_header->trampoline_start; unsigned long boot_error = 0; int cpu0_nmi_registered = 0; unsigned long timeout; idle->thread.sp = (unsigned long) (((struct pt_regs *) (THREAD_SIZE + task_stack_page(idle))) - 1); early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu); initial_code = (unsigned long)start_secondary; initial_stack = idle->thread.sp; /* * Enable the espfix hack for this CPU */ #ifdef CONFIG_X86_ESPFIX64 init_espfix_ap(cpu); #endif /* So we see what's up */ announce_cpu(cpu, apicid); /* * This grunge runs the startup process for * the targeted processor. */ if (get_uv_system_type() != UV_NON_UNIQUE_APIC) { pr_debug("Setting warm reset code and vector.\n"); smpboot_setup_warm_reset_vector(start_ip); /* * Be paranoid about clearing APIC errors. */ if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) { apic_write(APIC_ESR, 0); apic_read(APIC_ESR); } } /* * AP might wait on cpu_callout_mask in cpu_init() with * cpu_initialized_mask set if previous attempt to online * it timed-out. Clear cpu_initialized_mask so that after * INIT/SIPI it could start with a clean state. */ cpumask_clear_cpu(cpu, cpu_initialized_mask); smp_mb(); /* * Wake up a CPU in difference cases: * - Use the method in the APIC driver if it's defined * Otherwise, * - Use an INIT boot APIC message for APs or NMI for BSP. */ if (apic->wakeup_secondary_cpu) boot_error = apic->wakeup_secondary_cpu(apicid, start_ip); else boot_error = wakeup_cpu_via_init_nmi(cpu, start_ip, apicid, &cpu0_nmi_registered); if (!boot_error) { /* * Wait 10s total for first sign of life from AP */ boot_error = -1; timeout = jiffies + 10*HZ; while (time_before(jiffies, timeout)) { if (cpumask_test_cpu(cpu, cpu_initialized_mask)) { /* * Tell AP to proceed with initialization */ cpumask_set_cpu(cpu, cpu_callout_mask); boot_error = 0; break; } schedule(); } } if (!boot_error) { /* * Wait till AP completes initial initialization */ while (!cpumask_test_cpu(cpu, cpu_callin_mask)) { /* * Allow other tasks to run while we wait for the * AP to come online. This also gives a chance * for the MTRR work(triggered by the AP coming online) * to be completed in the stop machine context. */ schedule(); } } /* mark "stuck" area as not stuck */ *trampoline_status = 0; if (get_uv_system_type() != UV_NON_UNIQUE_APIC) { /* * Cleanup possible dangling ends... */ smpboot_restore_warm_reset_vector(); } /* * Clean up the nmi handler. Do this after the callin and callout sync * to avoid impact of possible long unregister time. */ if (cpu0_nmi_registered) unregister_nmi_handler(NMI_LOCAL, "wake_cpu0"); return boot_error; } int native_cpu_up(unsigned int cpu, struct task_struct *tidle) { int apicid = apic->cpu_present_to_apicid(cpu); unsigned long flags; int err; WARN_ON(irqs_disabled()); pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu); if (apicid == BAD_APICID || !physid_isset(apicid, phys_cpu_present_map) || !apic->apic_id_valid(apicid)) { pr_err("%s: bad cpu %d\n", __func__, cpu); return -EINVAL; } /* * Already booted CPU? */ if (cpumask_test_cpu(cpu, cpu_callin_mask)) { pr_debug("do_boot_cpu %d Already started\n", cpu); return -ENOSYS; } /* * Save current MTRR state in case it was changed since early boot * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync: */ mtrr_save_state(); /* x86 CPUs take themselves offline, so delayed offline is OK. */ err = cpu_check_up_prepare(cpu); if (err && err != -EBUSY) return err; /* the FPU context is blank, nobody can own it */ __cpu_disable_lazy_restore(cpu); common_cpu_up(cpu, tidle); /* * We have to walk the irq descriptors to setup the vector * space for the cpu which comes online. Prevent irq * alloc/free across the bringup. */ irq_lock_sparse(); err = do_boot_cpu(apicid, cpu, tidle); if (err) { irq_unlock_sparse(); pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu); return -EIO; } /* * Check TSC synchronization with the AP (keep irqs disabled * while doing so): */ local_irq_save(flags); check_tsc_sync_source(cpu); local_irq_restore(flags); while (!cpu_online(cpu)) { cpu_relax(); touch_nmi_watchdog(); } irq_unlock_sparse(); return 0; } /** * arch_disable_smp_support() - disables SMP support for x86 at runtime */ void arch_disable_smp_support(void) { disable_ioapic_support(); } /* * Fall back to non SMP mode after errors. * * RED-PEN audit/test this more. I bet there is more state messed up here. */ static __init void disable_smp(void) { pr_info("SMP disabled\n"); disable_ioapic_support(); init_cpu_present(cpumask_of(0)); init_cpu_possible(cpumask_of(0)); if (smp_found_config) physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map); else physid_set_mask_of_physid(0, &phys_cpu_present_map); cpumask_set_cpu(0, topology_sibling_cpumask(0)); cpumask_set_cpu(0, topology_core_cpumask(0)); } enum { SMP_OK, SMP_NO_CONFIG, SMP_NO_APIC, SMP_FORCE_UP, }; /* * Various sanity checks. */ static int __init smp_sanity_check(unsigned max_cpus) { preempt_disable(); #if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32) if (def_to_bigsmp && nr_cpu_ids > 8) { unsigned int cpu; unsigned nr; pr_warn("More than 8 CPUs detected - skipping them\n" "Use CONFIG_X86_BIGSMP\n"); nr = 0; for_each_present_cpu(cpu) { if (nr >= 8) set_cpu_present(cpu, false); nr++; } nr = 0; for_each_possible_cpu(cpu) { if (nr >= 8) set_cpu_possible(cpu, false); nr++; } nr_cpu_ids = 8; } #endif if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) { pr_warn("weird, boot CPU (#%d) not listed by the BIOS\n", hard_smp_processor_id()); physid_set(hard_smp_processor_id(), phys_cpu_present_map); } /* * If we couldn't find an SMP configuration at boot time, * get out of here now! */ if (!smp_found_config && !acpi_lapic) { preempt_enable(); pr_notice("SMP motherboard not detected\n"); return SMP_NO_CONFIG; } /* * Should not be necessary because the MP table should list the boot * CPU too, but we do it for the sake of robustness anyway. */ if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) { pr_notice("weird, boot CPU (#%d) not listed by the BIOS\n", boot_cpu_physical_apicid); physid_set(hard_smp_processor_id(), phys_cpu_present_map); } preempt_enable(); /* * If we couldn't find a local APIC, then get out of here now! */ if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) && !boot_cpu_has(X86_FEATURE_APIC)) { if (!disable_apic) { pr_err("BIOS bug, local APIC #%d not detected!...\n", boot_cpu_physical_apicid); pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n"); } return SMP_NO_APIC; } /* * If SMP should be disabled, then really disable it! */ if (!max_cpus) { pr_info("SMP mode deactivated\n"); return SMP_FORCE_UP; } return SMP_OK; } static void __init smp_cpu_index_default(void) { int i; struct cpuinfo_x86 *c; for_each_possible_cpu(i) { c = &cpu_data(i); /* mark all to hotplug */ c->cpu_index = nr_cpu_ids; } } /* * Prepare for SMP bootup. The MP table or ACPI has been read * earlier. Just do some sanity checking here and enable APIC mode. */ void __init native_smp_prepare_cpus(unsigned int max_cpus) { unsigned int i; smp_cpu_index_default(); /* * Setup boot CPU information */ smp_store_boot_cpu_info(); /* Final full version of the data */ cpumask_copy(cpu_callin_mask, cpumask_of(0)); mb(); for_each_possible_cpu(i) { zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL); zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL); zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL); } set_cpu_sibling_map(0); switch (smp_sanity_check(max_cpus)) { case SMP_NO_CONFIG: disable_smp(); if (APIC_init_uniprocessor()) pr_notice("Local APIC not detected. Using dummy APIC emulation.\n"); return; case SMP_NO_APIC: disable_smp(); return; case SMP_FORCE_UP: disable_smp(); apic_bsp_setup(false); return; case SMP_OK: break; } default_setup_apic_routing(); if (read_apic_id() != boot_cpu_physical_apicid) { panic("Boot APIC ID in local APIC unexpected (%d vs %d)", read_apic_id(), boot_cpu_physical_apicid); /* Or can we switch back to PIC here? */ } cpu0_logical_apicid = apic_bsp_setup(false); pr_info("CPU%d: ", 0); print_cpu_info(&cpu_data(0)); if (is_uv_system()) uv_system_init(); set_mtrr_aps_delayed_init(); smp_quirk_init_udelay(); } void arch_enable_nonboot_cpus_begin(void) { set_mtrr_aps_delayed_init(); } void arch_enable_nonboot_cpus_end(void) { mtrr_aps_init(); } /* * Early setup to make printk work. */ void __init native_smp_prepare_boot_cpu(void) { int me = smp_processor_id(); switch_to_new_gdt(me); /* already set me in cpu_online_mask in boot_cpu_init() */ cpumask_set_cpu(me, cpu_callout_mask); cpu_set_state_online(me); } void __init native_smp_cpus_done(unsigned int max_cpus) { pr_debug("Boot done\n"); nmi_selftest(); impress_friends(); setup_ioapic_dest(); mtrr_aps_init(); } static int __initdata setup_possible_cpus = -1; static int __init _setup_possible_cpus(char *str) { get_option(&str, &setup_possible_cpus); return 0; } early_param("possible_cpus", _setup_possible_cpus); /* * cpu_possible_mask should be static, it cannot change as cpu's * are onlined, or offlined. The reason is per-cpu data-structures * are allocated by some modules at init time, and dont expect to * do this dynamically on cpu arrival/departure. * cpu_present_mask on the other hand can change dynamically. * In case when cpu_hotplug is not compiled, then we resort to current * behaviour, which is cpu_possible == cpu_present. * - Ashok Raj * * Three ways to find out the number of additional hotplug CPUs: * - If the BIOS specified disabled CPUs in ACPI/mptables use that. * - The user can overwrite it with possible_cpus=NUM * - Otherwise don't reserve additional CPUs. * We do this because additional CPUs waste a lot of memory. * -AK */ __init void prefill_possible_map(void) { int i, possible; /* no processor from mptable or madt */ if (!num_processors) num_processors = 1; i = setup_max_cpus ?: 1; if (setup_possible_cpus == -1) { possible = num_processors; #ifdef CONFIG_HOTPLUG_CPU if (setup_max_cpus) possible += disabled_cpus; #else if (possible > i) possible = i; #endif } else possible = setup_possible_cpus; total_cpus = max_t(int, possible, num_processors + disabled_cpus); /* nr_cpu_ids could be reduced via nr_cpus= */ if (possible > nr_cpu_ids) { pr_warn("%d Processors exceeds NR_CPUS limit of %d\n", possible, nr_cpu_ids); possible = nr_cpu_ids; } #ifdef CONFIG_HOTPLUG_CPU if (!setup_max_cpus) #endif if (possible > i) { pr_warn("%d Processors exceeds max_cpus limit of %u\n", possible, setup_max_cpus); possible = i; } pr_info("Allowing %d CPUs, %d hotplug CPUs\n", possible, max_t(int, possible - num_processors, 0)); for (i = 0; i < possible; i++) set_cpu_possible(i, true); for (; i < NR_CPUS; i++) set_cpu_possible(i, false); nr_cpu_ids = possible; } #ifdef CONFIG_HOTPLUG_CPU /* Recompute SMT state for all CPUs on offline */ static void recompute_smt_state(void) { int max_threads, cpu; max_threads = 0; for_each_online_cpu (cpu) { int threads = cpumask_weight(topology_sibling_cpumask(cpu)); if (threads > max_threads) max_threads = threads; } __max_smt_threads = max_threads; } static void remove_siblinginfo(int cpu) { int sibling; struct cpuinfo_x86 *c = &cpu_data(cpu); for_each_cpu(sibling, topology_core_cpumask(cpu)) { cpumask_clear_cpu(cpu, topology_core_cpumask(sibling)); /*/ * last thread sibling in this cpu core going down */ if (cpumask_weight(topology_sibling_cpumask(cpu)) == 1) cpu_data(sibling).booted_cores--; } for_each_cpu(sibling, topology_sibling_cpumask(cpu)) cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling)); for_each_cpu(sibling, cpu_llc_shared_mask(cpu)) cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling)); cpumask_clear(cpu_llc_shared_mask(cpu)); cpumask_clear(topology_sibling_cpumask(cpu)); cpumask_clear(topology_core_cpumask(cpu)); c->phys_proc_id = 0; c->cpu_core_id = 0; cpumask_clear_cpu(cpu, cpu_sibling_setup_mask); recompute_smt_state(); } static void remove_cpu_from_maps(int cpu) { set_cpu_online(cpu, false); cpumask_clear_cpu(cpu, cpu_callout_mask); cpumask_clear_cpu(cpu, cpu_callin_mask); /* was set by cpu_init() */ cpumask_clear_cpu(cpu, cpu_initialized_mask); numa_remove_cpu(cpu); } void cpu_disable_common(void) { int cpu = smp_processor_id(); remove_siblinginfo(cpu); /* It's now safe to remove this processor from the online map */ lock_vector_lock(); remove_cpu_from_maps(cpu); unlock_vector_lock(); fixup_irqs(); } int native_cpu_disable(void) { int ret; ret = check_irq_vectors_for_cpu_disable(); if (ret) return ret; clear_local_APIC(); cpu_disable_common(); return 0; } int common_cpu_die(unsigned int cpu) { int ret = 0; /* We don't do anything here: idle task is faking death itself. */ /* They ack this in play_dead() by setting CPU_DEAD */ if (cpu_wait_death(cpu, 5)) { if (system_state == SYSTEM_RUNNING) pr_info("CPU %u is now offline\n", cpu); } else { pr_err("CPU %u didn't die...\n", cpu); ret = -1; } return ret; } void native_cpu_die(unsigned int cpu) { common_cpu_die(cpu); } void play_dead_common(void) { idle_task_exit(); reset_lazy_tlbstate(); amd_e400_remove_cpu(raw_smp_processor_id()); /* Ack it */ (void)cpu_report_death(); /* * With physical CPU hotplug, we should halt the cpu */ local_irq_disable(); } static bool wakeup_cpu0(void) { if (smp_processor_id() == 0 && enable_start_cpu0) return true; return false; } /* * We need to flush the caches before going to sleep, lest we have * dirty data in our caches when we come back up. */ static inline void mwait_play_dead(void) { unsigned int eax, ebx, ecx, edx; unsigned int highest_cstate = 0; unsigned int highest_subcstate = 0; void *mwait_ptr; int i; if (!this_cpu_has(X86_FEATURE_MWAIT)) return; if (!this_cpu_has(X86_FEATURE_CLFLUSH)) return; if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF) return; eax = CPUID_MWAIT_LEAF; ecx = 0; native_cpuid(&eax, &ebx, &ecx, &edx); /* * eax will be 0 if EDX enumeration is not valid. * Initialized below to cstate, sub_cstate value when EDX is valid. */ if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) { eax = 0; } else { edx >>= MWAIT_SUBSTATE_SIZE; for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) { if (edx & MWAIT_SUBSTATE_MASK) { highest_cstate = i; highest_subcstate = edx & MWAIT_SUBSTATE_MASK; } } eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) | (highest_subcstate - 1); } /* * This should be a memory location in a cache line which is * unlikely to be touched by other processors. The actual * content is immaterial as it is not actually modified in any way. */ mwait_ptr = ¤t_thread_info()->flags; wbinvd(); while (1) { /* * The CLFLUSH is a workaround for erratum AAI65 for * the Xeon 7400 series. It's not clear it is actually * needed, but it should be harmless in either case. * The WBINVD is insufficient due to the spurious-wakeup * case where we return around the loop. */ mb(); clflush(mwait_ptr); mb(); __monitor(mwait_ptr, 0, 0); mb(); __mwait(eax, 0); /* * If NMI wants to wake up CPU0, start CPU0. */ if (wakeup_cpu0()) start_cpu0(); } } void hlt_play_dead(void) { if (__this_cpu_read(cpu_info.x86) >= 4) wbinvd(); while (1) { native_halt(); /* * If NMI wants to wake up CPU0, start CPU0. */ if (wakeup_cpu0()) start_cpu0(); } } void native_play_dead(void) { play_dead_common(); tboot_shutdown(TB_SHUTDOWN_WFS); mwait_play_dead(); /* Only returns on failure */ if (cpuidle_play_dead()) hlt_play_dead(); } #else /* ... !CONFIG_HOTPLUG_CPU */ int native_cpu_disable(void) { return -ENOSYS; } void native_cpu_die(unsigned int cpu) { /* We said "no" in __cpu_disable */ BUG(); } void native_play_dead(void) { BUG(); } #endif